1. Field of the Invention
The present invention relates to an apparatus for controlling ignition in an internal combustion engine. The apparatus according to the present invention is used in an AC continuous-discharge type ignition apparatus for restricting the primary coil current of an ignition coil.
2. Description of the Related Art
In a conventional AC continuous-discharge type ignition apparatus for a spark ignition type internal combustion engine, the discharge duration of a spark plug can be prolonged during a single combustion cycle of the engine, as needed. The apparatus has a high average discharging current, e.g., 50 mA or higher, and allows easy ignition of a fuel-air mixture.
However, the conventional ignition apparatus generates only one ignition instruction signal. When this signal is at H level, there is a delay time of 0.5 to 1 msec from when the apparatus is rendered conductive until ignition start time. Therefore, spark timings cannot be controlled accurately. In addition, since ignition energy for the first discharge is insufficient, a sufficiently high voltage cannot be generated.
The conventional ignition apparatus is disclosed in, for example, U.S. Pat. No. 4,356,807.